define([ 'frameworks/knockout-2.1.0' ], function(ko) {
	
	ko.bindingHandlers['class'] = {
		    'update': function(element, valueAccessor) {
		        if (element['__ko__previousClassValue__']) {
		            $(element).removeClass(element['__ko__previousClassValue__']);
		        }
		        var value = ko.utils.unwrapObservable(valueAccessor());
		        $(element).addClass(value);
		        element['__ko__previousClassValue__'] = value;
		    }
		};
	
	return ko;
});